The Florida Supreme Court in July put his execution, originally set for Aug. 2, on hold after his lawyers raised objections to the state’s use of a new drug as part of the lethal injection formula. Department of Corrections officials substituted pentobarbital for a drug no longer manufactured as the first of the three-drug lethal injection “cocktail.”

Since his conviction for the 1978 killing of Coral Gables police officer Louis Pena, Valle has been sentenced to death and re-sentenced three times in legal wrangling that eventually reached the U.S. Supreme Court, which overturned his death penalty in 1987. Courts later reaffirmed his death penalty conviction.

On Aug. 23, the Florida Supreme Court On Tuesday, the court approved the Department of Corrections’ new drug protocol, saying it did not pose a substantial risk of harm to the inmate.

Valle’s lawyers are also pursuing other appeals, including with the U.S. Supreme Court.